The River Teeth Literary Nonfiction Book Prize is an annual contest that seeks a book-length manuscript of literary nonfiction. Administered by the journal River Teeth, the prize is a significant venue for sustained nonfiction that blends reportage, memoir, and essayistic inquiry. The contest is open to all writers, with a particular encouragement for underrepresented voices, including BIPOC, LGBTQ+, and disabled writers. The winning manuscript will be published by the University of New Mexico Press, a respected academic press with a strong list in creative nonfiction and regional studies. All submissions are initially screened by the co-editors of River Teeth, ensuring that each manuscript receives careful editorial attention before the guest judge, Ander Monson, makes the final selection. Monson, a noted author and editor, brings a discerning eye for innovative and intellectually rigorous nonfiction. The winner receives a $1,000 prize and publication, while all U.S. entrants who provide a mailing address will receive a one-year subscription to River Teeth, beginning in the spring. This subscription offers not only a tangible benefit but also an introduction to the journal's curatorial sensibility. The contest operates on a fixed deadline of October 31, 2026, with a submission fee of $27. The fee supports the journal and the prize infrastructure, and the subscription serves as a partial return for entrants. The prize is designed for writers who have completed a book-length manuscript and are seeking a path to publication. The University of New Mexico Press's commitment to literary nonfiction ensures that the winning book will be produced with care and distributed to a broad readership. This is not a contest for excerpts or proposals; it requires a full manuscript, signaling a serious investment from both the writer and the press.